Water treatment process

ABSTRACT

A system and process for treating water are described. Water may be purified by passing feed water through an electrochemical deionization device. The water may be suitable for cooking, washing, and beverage production.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a water treatment system and processand, more particularly, to a water treatment system and process forproducing purified water for human consumption.

2. Description of the Related Art

Purified water is used in many industries including the chemical,foodstuffs, electronics, power, medical and pharmaceutical industries,as well as for human consumption. Typically, prior to use in any one ofthese fields, the water is treated to reduce the level of contaminantsto acceptable levels. These treatment techniques include disinfection,distillation, filtration, ion exchange, reverse osmosis, photooxidation,ozonation, and combinations thereof.

Various levels of purity may be required for different end uses. Waterquality may be regulated by various government agencies and tradeorganizations including the U.S. Environmental Protection Agency (EPA)and the Food and Drug Administration (FDA).

The beverage industry consumes a significant amount of water that mustmeet environmental, as well as health requirements. In addition toregulations that assure that beverages are safe for consumption, thebeverage industry faces additional standards that are grounded inquality control. For example, a water supply that meets federalregulations for microorganisms may not satisfy a beverage producer'squality control standards for additional parameters such as taste andodor that may affect product quality. These standards may includehardness (calcium, magnesium and silica content), bicarbonate, pH, totalsuspended solids (TSS), total dissolved solids (TDS), color, taste, andtemperature.

Control of these parameters is complicated by the decentralizedstructure of the beverage industry itself. For instance, a world-wideproducer of beverages typically has a number of points of productionthroughout the world. Each of these points may access a water supplythat is different than those used by other plants. Although federalregulations may help to standardize health and safety requirements forwater used in beverage production in the United States, these standardsmay differ greatly from those in other countries. These differentstandards may impact factors such as taste, odor, and appearance. Thismay be important to producers who market a beverage under a singletrademark throughout a large territory. For example, a customer whoconsumes a beverage in one part of the country will expect the sameappearance and taste from that beverage regardless of where it ispurchased. To assure this type of consistency, the beverage producer mayrequire that the water used in beverage production meet the same, orsimilar standards, regardless of where the beverage is produced. One wayof achieving this goal is through the use of water treatment processes.

Assuring water quality for a number of bottling plants typicallyrequires the imposition of measurable and attainable water qualitystandards that can be achieved at minimal cost for various types of feedwater that may be used. These quality control issues become even moredifficult to implement and control when fountain outlets are included.Fountain outlets are typically those locations where beverages areproduced for immediate on-site, or nearby, consumption. Generally, at afountain outlet, water is mixed with a flavor syrup and, in the case ofcarbonated beverages, carbon dioxide. The beverage may then be serveddirectly to the consumer. Among the advantages provided by fountainoutlets are the savings realized from not shipping or storing a bulkyproduct. Because of these and other advantages, millions of licensedfountain outlets are in operation worldwide.

Consumers typically expect consistent quality in their beverages whetherthey choose to purchase a can or bottle from a store, or a cup from afountain outlet. As water quality can affect the taste and appearance ofa beverage, it is important for beverage licensors to provide waterquality standards for fountain outlets as well as for bottlers. Thereare several factors that may influence water quality standards forfountain outlets, two of which are available sources of water and thecost of treating the water.

As fountain outlets may exist in various locations, the water sourcesused to produce fountain beverages may also differ. These water sourcesmay include, for example, municipal water supplies, surface water, wellwater, precipitated water and desalinated sea water. Each of thesesources may supply water of varying quality, and even within one type ofwater supply, for instance, well water, the type and quality of thewater supplied may not be consistent from location to location.

Additionally, fountain outlets are commonly found at restaurants, snackbars, convenience stores, and the like, and at many of these locationsthe cost of water treatment may have an impact on profitability. Thus,beverage producers and licensors must balance the needs of the consumerfor consistent taste and appearance with the outlet's need for alow-cost water supply. In addition, the outlet operator is concernedwith reliability; if the water treatment system fails, beverageproduction at a fountain outlet comes to a halt. System maintenance isalso important and typically the goal is for less frequent maintenancewith less complicated procedures.

The capacity of the water treatment system is also different from thatrequired by a bottler. Typically, the output requirements are much lowerat fountain outlets, yet the system must still be able to produce anadequate supply of high quality water at times of peak demand, and sincefountain outlets may go through periods of non-use, a water treatmentsystem should be able to supply high quality water on demand after aperiod of non-use.

Different well water sources may provide a challenge for those designingwater treatment systems for fountain outlets. Well water may containhigh concentrations of dissolved matter, such as bicarbonate anddissolved solids, as well as suspended material that may contribute totaste and appearance. For example, water may be hard, having a highconcentration of calcium, magnesium or silica and may contain additionalionic materials contributing to total dissolved solids (TDS). Inaddition, organic materials, as well as dissolved gases, may be present,pH and buffering capacity may vary widely, and the composition of thewater from a single well may vary over time or with different levels ofuse.

Various water treatment systems and processes exist for producing highpurity water for use in beverage production and other industries. Amongthese systems are disinfection units, such as chlorinators andozonators, filters, water softeners, reverse osmosis systems, andchemical ion exchange devices.

Disinfection units are typically used to reduce the concentration ofviable microorganisms in a water supply. This may be accomplished byadding a disinfectant, for example, chlorine, ozone, or ammonia,directly to the water supply so that pathogenic organisms are destroyed.Alternatively, microorganisms may be destroyed by a process, such asheating or treatment with ultraviolet light, or microorganisms may bephysically removed from the water by filtration. When a chemicaldisinfectant is used, it is often desirable to remove the disinfectantfrom the water prior to consumption, and this may be accomplished in anumber of ways including chemical neutralization and removal byfiltration.

Filtration is used to remove suspended matter from a water supply butmay also aid in the removal of dissolved or colloidal species. Filtersmay be structured from a variety of materials including particulatematter such as sand, diatomaceous earth, or granular activated carbon(GAC), or may be based on a membrane that may be composed of a number ofdifferent materials including polymers and fibrous materials. Filterstypically work by preventing the passage of suspended material whileallowing water to pass through. One way of rating a filter is by its“pore size” which provides information as to what size particle will beretained by the filter. Some methods, such as hyperfiltration, may havepore sizes small enough to exclude some dissolved species.

Water may be adversely affected by the presence of calcium or magnesiumions. Known as “hardness,” a high concentration of these cations,typically more than 200 ppm (mg/L as CaCO₃), results in a water that mayleave scale or other deposits on equipment and piping. Typically,calcium and magnesium are removed from water (softened) by exchangingthe calcium and magnesium ions for alternative cations, often sodium.Water softeners typically contain resin beads that exchange two sodiumions for every calcium or magnesium ion that is removed from the treatedwater. Periodically, the water softener may be recharged to resupply theresin beads with an adequate supply of sodium or alternative cations.

Reverse osmosis (RO) is a filtration technique that provides for theremoval of dissolved species from a water supply. Typically, water issupplied to one side of an RO membrane at elevated pressure and purifiedwater is collected from the low pressure side of the membrane. The ROmembrane is structured so that water may pass through the membrane whileother compounds, for example, dissolved ionic species, are retained onthe high pressure side. Some species however, such as bicarbonate, maynot be retained. The “concentrate” that contains an elevatedconcentration of ionic species may then be discharged or recycled, whilethe permeate, typically containing a reduced concentration of ionicspecies, is collected for later use.

A system currently used to purify water for use in beverage productionsystems is illustrated in FIG. 1. Feed water passes through conduit 150into particulate filter 110 which helps to remove any particulate matterthat may be suspended in the feed water. The water then passes throughconduit 151 into pump 140. Pump 140 pressurizes the water which proceedsthrough conduit 152 into RO device 120. In RO device 120, purified wateris collected from the low pressure side of the membrane and passesthrough conduit 153 to storage tank 130. When an adequate supply ofpurified water is contained in storage type 130, it may be drawn to abeverage production system through a pump (not shown) connected toconduit 154.

Deionization units may also be used to remove a variety of ionic speciesfrom a water supply. Deionization units typically employ either chemicalor electrical deionization to replace specific cations and anions withalternative ions. In chemical deionization, an ion exchange resin isemployed to replace ions contained in the feed water. The ions on theresin are recharged by periodically passing a recharging fluid throughthe resin bed. This fluid may be an acid that replenishes the supply ofhydrogen ions on the cation exchange resin. For anion exchange resins,the resin may be replenished by passing a base through the resin,replacing any bound anions with hydroxyl groups and preparing the resinfor additional anion removal.

In electrodeionization, however, the resin or resins may be replenishedby hydrogen and hydroxyl ions that are produced from the splitting ofwater during the application of electric current to the deionizationunit. In continuous electrodeionization (CEDI), the ions are replacedwhile the feed water is being treated, and thus no separate rechargingstep is required. Typically, the feed water is first passed through anRO membrane to reduce the total concentration of ionic species presentin the feed water. This reduces the load on the CEDI unit and preventsscale and deposits from building up in the concentrating compartment ofthe unit.

SUMMARY OF THE INVENTION

In one aspect a method of purifying water is provided, the methodincluding providing a feed water, reducing a hardness of the water to arange of 5-100 ppm as CaCO₃, reducing an alkalinity of the water to arange of 10-100 ppm as CaCO₃, and supplying the water of reducedalkalinity and reduced hardness for human consumption.

In another aspect, a water treatment system is provided, the watertreatment system including a feed water inlet, an electrochemicaldeionization device in fluid communication with the feed water inlet andwith a feed water outlet, and a beverage production device in fluidcommunication with the feed water outlet.

In another aspect, a method for purifying water for beverage productionis provided, the method comprising the steps of supplying feed water toan electrochemical deionization device to produce a purified waterstream, and feeding the purified water stream to a fountain beverageproduction device.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred, non-limiting embodiments of the present invention will bedescribed by way of example with reference to the accompanying drawings,in which:

FIG. 1 is a schematic drawing of a prior art water treatment system.

FIG. 2 is a schematic drawing of an embodiment of the apparatus of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a water treatment system andprocess for effectively treating water for human consumption. Theinvention may be used with a variety of feed waters to produce aconsistent, high quality water supply to meet the requirements of thefood and beverage industry. In various embodiments, purified water maybe used, for example, in cooking, drinking, hot and cold beverageproduction, brewing, washing and/or ice making.

Beverage producers may have specific requirements for which theinvention may be particularly well suited. For example, fountainbeverage producers may access water supplies that differ greatly fromthose used by other producers, yet the production water specificationsrequired by beverage companies may be precise, or at least within aspecific range, from one point of production to the next. Thus, oneproducer using a municipal surface water supply as a source may berequired to reduce levels of chlorine while another producer accessingits own well may be required to reduce levels of bicarbonate andcalcium. In one aspect, the present invention may be applicable to alarge cross-section of these producers because of its versatility inproducing a consistent supply of treated water from a variety ofsources.

In one aspect, the present invention may be used to provide purifiedwater to a beverage production device. A beverage production device isany device that uses water to produce a beverage for human consumption.The beverage production device may be used to produce carbonated ornon-carbonated beverages and may also provide purified drinking water.Some beverage production devices provide a beverage by adding a syrupconcentrate to water and, if carbonated, carbon dioxide. Fountainbeverage production devices are those that produce beverages forimmediate consumption on site, or nearby, rather than for storage orshipment. Fountain beverages are typically produced using chilled waterbut are not refrigerated after production. Fountain beverage devices areoften found in restaurants, snack bars, gas stations and conveniencestores. In some cases, they may be portable.

In another aspect, an electrochemical deionization device may be used toproduce purified water. An electrochemical deionization device can beany device that employs an electric current or electric field to reducethe concentration of ionic compounds in a water sample. Someelectrochemical deionization devices of the invention have no movingparts and/or have no filtration membrane. Examples of electrochemicaldeionization devices include electrodialysis (ED), electrodialysisreversal (EDR) electrodeionization (EDI), capacitive deionization,continuous electrodeionization (CEDI), and reversible continuouselectrodeionization (RCEDI).

Electrochemical deionization devices, methods of use, and methods ofmaking are described by, for example, Giuffrida et al. in U.S. Pat. Nos.4,632,745, 4,925,541, 4,956,071 and 5,211,823, by Ganzi in U.S. Pat. No.5,259,936, by Ganzi et al., in U.S. Pat. No. 5,316,637, by Oren et al.in U.S. Pat. No. 5,154,809, by Kedem in U.S. Pat. No. 5,240,579, byLiang et al. in U.S. patent application Ser. No. 09/954,986 and U.S.Pat. No. 6,649,037, by Andelman in U.S. Pat. No. 5,192,432, Martin et.al. in U.S. Pat. No. 5,415,786, and by Farmer in U.S. Pat. No.5,425,858. All patents and patent applications cited herein are herebyincorporated by reference herein.

Water treatment systems to purify water for beverage production, such asat fountain beverage outlets, have traditionally been designed using avariety of devices that may be included or excluded based on factorssuch as the type of water supply, the location, and the anticipatedwater demand. For example, a site using well water might include achemical ion exchange water softener while a site using a municipalwater supply might use a reverse osmosis (RO) device, a storage tank,and a pump. In one aspect, the present invention provides for a systembased on one or more electrochemical deionization devices to produceconsistent quality purified water. The system can be installed atdifferent locations accessing different types of supply waters. Anelectrochemical deionization device, such as a CEDI or RCEDI, may be“tuned” to provide a water that contains neither too many nor too fewimpurities for beverage production. For example, if a feed watercontains a high level of hardness and TDS, process conditions for thedevice may be altered to remove a greater amount of impurities. If afeed water contains lower levels of impurities, the device may be tunedto remove fewer contaminants to avoid producing a water that is toopure. The device may either be tuned manually by an operator, orautomatically, in response to a change in a condition, such as productwater conductivity or demand rate. Thus, changes in the system such asrate of demand, device efficiency, or feed water quality may beautomatically compensated for by tuning. The device may require littleor no maintenance as many changes in efficiency may be compensated forby tuning rather than by replacing components, for example. The tuningmay be transparent to the operator.

In one embodiment, the device may be dedicated to supplying water onlyfor beverage production and the product output of the device may beplumbed exclusively to a beverage production system, such as a fountainoutlet. In such a case, an electrochemical deionization device is inexclusive fluid communication with a beverage production device. Inother embodiments, product water may be used for other purposes, suchas, for example, food preparation, drinking water, and dish washing.

Typically, RO systems require a significant amount of storage becausewhile they may be efficient at removing some dissolved matter from awater supply, these systems may not be able to adequately provide therequired flow on demand, but rather are configured to gather treatedwater in a storage device from which it can be drawn when needed. Thus,the present invention may provide a number of advantages overtraditional RO based systems. Electrochemical deionization systems mayprovide constant or on demand flow rates of greater than 1, 2, 3, 5 or10 gal/min. For some embodiments, such as those used with fountainbeverage dispensers, an electrochemical deionization device may haveproduction capacities of less than 20, less than 10 or less than 5gal/min. Smaller capacity systems may be sized most appropriately foruse in restaurants, concessions stands, convenience stores, and thelike. Systems of these capacities may be sized to fit in a footprintarea of about 9 ft² and may be used in many fountain outlets withoutrequiring the building of additional space for installation of a watertreatment system.

Ease of use and economy of operation may be important to a fountainbeverage operator. Typically, fountain operators are not trained inwater treatment and prefer systems that run themselves without constantmonitoring or input from the operator. The system of the presentinvention may be well suited for this environment because it may beself-monitoring and may be able to supply on-demand water 24 hours a daywithout a requirement of pre-testing the quality of the water. Inaddition, when maintenance is required, it is preferred that theprocedures be simple and routine. For example, the system may use GACcartridges and particulate filter cartridges that can be switched out atpre-set intervals or when certain parameters, for instance, waterquality, reach certain levels.

An electrochemical deionization device may be partially or totallymaintenance-free. For example, in an RCEDI system any scale build-up maybe halted or reversed by switching the polarity of the system. Resin maybe recharged by in situ hydrolysis within a compartment or at aninterface with a membrane. A temporary or permanent decrease or increasein efficiency may be compensated for by a change in process conditions,which may occur automatically. A change in process conditions mayinclude a change in voltage or current or a change in flow rates throughdepletion, concentrating, or electrode compartments, or any combinationthereof.

As described in U.S. Pat. No. 4,956,071, a reversible continuouselectrodeionization (RCEDI) device is a CEDI device that is configuredto periodically reverse the polarity of the electrodes. Dilution andconcentration compartments may also alternate functions. In someembodiments, an RCEDI device that may be used with the present inventioncan be operated with little or no maintenance. Furthermore, if an RCEDIdevice fails, it typically does so slowly, giving the operator theopportunity to have the device serviced while still producing acceptablequality water. Alternatively, if an RO system fails, it may happeninstantaneously, resulting in the inability to produce purified wateruntil it is repaired. An RCEDI device may be operated by a manual orautomatic controller that can adjust process conditions in response to,for example, feed water or product water quality.

In one aspect, a system of the present invention may have lower powerrequirements than do alternative systems. For example, while RO andchemical deionization systems typically require additional pumps toachieve the pressures necessary for proper operation, the presentinvention may be capable of producing acceptable quality water at tappressures, and may be capable of operating at feed pressures below about20 psig. In some embodiments, no pumps are used and the only pressurerequired is provided by the tap pressure. A system may be designed usingreadily available power supplies, eliminating the need for expensivewiring options.

Space requirements may also be important, particularly for fountainbeverage producers. By optionally providing for the elimination of suchbulky components as, for example, pumps, storage tanks, and powersupplies, the system may be installed in a relatively small area,possibly without requiring the relocation of production equipment thatis already in place. In addition, by eliminating additional pumps, forexample, the system may provide significantly quieter operation thanalternative systems such as RO or ion exchange and therefore may beparticularly appropriate at sites where noise may be a concern.

The disposal of brines and concentrates may also be significantlyreduced. Typically, water softeners and chemical deionization devices,among others, require periodic recharging that can result in significantgeneration of waste water that may have low pH levels or contain highlevels of salts. Disposal of waste water may trigger additionalregulatory requirements that the user must meet. This may be of greaterconcern in areas where regulations prohibit or regulate the discharge ofbrines and other recharging fluids to a local septic system or otherwaste water disposal facility. The present system, by replacing suchdevices with an electrochemical deionization device, may greatly reducethe amount of these fluids that are discharged to waste. In someembodiments, there may be no net increase to the total dissolved solidsthat are received in the tap water.

Water use may be minimized by implementing one or more aspects of thepresent invention. The system of the present invention may be moreefficient in its use of water than alternative systems, such as RO. Forexample, the system of the present invention may operate so that arecovery of greater than about 55, 60, 65, 70 or 75% of the feed wateris obtainable. This compares favorably to the 50-55% recovery that istypically obtainable from a two-pass RO system producing comparablequality water. In addition, upon start-up, the present invention mayproduce water that is immediately available for beverage production.Alternative systems may require that an initial quantity of water bedischarged before the supply is of sufficient quality to be used. Forexample, after recharge, a chemical deionization system may producewater at a pH of about 3 for a period of time. Water at this pH may notbe suitable for beverage production and may therefore require dischargeto waste. Furthermore, the output of the present system may be adjustedover a range of about 50-150% of the designed output and still produceacceptable quality water. This means that feed water need not be wastedin producing water of greater purity than is required for a specificapplication. Alternatively, if water quality needs to be raised, similaradjustments to process conditions may be made to achieve the desiredresults. Adjustments may be made manually or automatically by acontroller.

One embodiment of the invention is shown in FIG. 2. Prior to enteringthe system through conduit 11, feed water may first be pretreated in anynumber of ways. “Pretreatment” means that water quality is altered priorto entering an electrochemical device. Pretreatment may include addingor removing substances from the water, or altering a quality of thewater. For example, water may be disinfected through the use of chemicalor physical techniques. Chemical disinfection typically includes theaddition of an oxidant to the water supply. These oxidants may includechlorine, chloramine, ozone, or ammonia. If water is to be disinfectedthrough non-chemical techniques, it may be heated for a length of timeat a temperature that is adequate to destroy microorganisms.Alternatively, the water may be disinfected with radiation such asultraviolet light or may be disinfected by filtering out microorganismsof concern.

Aeration may also supply some benefits as a pretreatment step. Aerationinvolves bubbling a quantity of air (or other gas) through the watersupply to facilitate chemical reactions or to physically removecompounds from the water. For example, aeration may help in removingresidual disinfectants such as chlorine and chloramine. In addition,aeration may aid in removing volatile and semi-volatile organiccompounds, including trihalomethanes (THMs), that may be present in thewater. Aeration may also reduce the concentration of hydrogen sulfide(H₂S) and radon in the feed water as well as serve to oxidize organicsand/or metals such as iron. The oxidation of iron in solution may resultin the formation of a precipitate, such as iron oxide, that may beeasier to separate from the feed water than dissolved iron. It may bepreferred that feed water containing relatively high concentrations ofiron is pretreated to remove the iron from solution as it may contributeto taste and odor in a beverage.

Another pretreatment technique that may be used is treating with aflocculent. The addition of a flocculent, for example, alum, may help incoagulating suspended particles so that they are more easily separatedfrom the feed water. This may result in a decrease in the particulatesthat need to be filtered out in the particulate filter of the invention,and thus may result in prolonging the life of the filter. The use of aflocculent may be combined with aeration.

In one aspect, the invention provides a water that is less pure thanwater that may be produced by other purification methods. Often, abeverage producer may prefer a water that is pure, but not too pure. Forexample, if a water contains very low levels of TDS, for example, lessthan about 50 ppm, less than about 20 ppm, or less than about 10 ppm,the water may negatively affect the taste of the beverage. In addition,other characteristics such as corrossivity may be affected byexcessively pure water. Therefore, some water purification techniques,for example, RO, may provide a water that is more pure than is typicallydesirable for beverage production devices.

One way of providing a water containing enough TDS and alkalinity tomeet taste requirements is to blend a pure water (that would be too pureby itself) with a feed water or other water containing high levels ofalkalinity and TDS. A proper blending ratio may result in a water havingadequate taste characteristics. Of course, this may involve additionalsteps, valves, pumps, etc. Minerals or other soluble species may also beadded (or added back) to a pure water. In some embodiments, beveragequality water may be produced without adding substances to a purifiedwater.

In another aspect, purified water may be produced, for humanconsumption, for example, without blending a purified water with a lesspure water to obtain a desired range of dissolved species, such as, forexample, minerals, salts, hardness, alkalinity, CO₂ or TDS. In someembodiments, one or more impurities in a feed water are reduced to adesirable level without mixing waters of high and low impurityconcentration. The levels of impurities, such as, for example, hardness,TDS and alkalinity may be reduced to desired levels in a single stepusing a single device, such as an electrochemical deionization device.The water need not first be purified to a level below a desired rangeand does not need to be blended with a water containing impurities in ahigher range, as may be done, for example, with some RO systems. Thesystem may be operated without purifying any of the water to a levelbelow that of a target level for one or more impurities. Usingelectrochemical deionization, target ranges can be reached directly byadjusting the operating conditions of the electrochemical deionizationdevice.

In some embodiments, an electrochemical deionization device can becontrolled and adjusted for water quality. The option of controlling andadjusting product water quality can expand the types and quality of feedwater that can be used to make purified water of a consistent,predetermined quality that may be suitable for beverage production.Process conditions such as voltage, amperage, flow rate and reversalcycle timing may be altered manually or automatically, and may be donein response to, for example, purified water quality, concentrate waterquality, or feed water quality. Process conditions may also be adjusteddue to changes in factors unrelated to water quality, such astemperature and demand rate. Altering a process condition may includealtering the removal efficiency of the device. For example, if a levelof TDS is detected that is too low, the efficiency of the device may bereduced so that fewer impurities are removed from the water. This may bedone, for example, by reducing the current to a CEDI or RCEDI device.Likewise, if TDS levels are above a desired range, the efficiency of thedevice may be increased by increasing the current or reducing flow. Inother embodiments, efficiency may be varied by turning on and off(cycling) the electrical feed to the electrochemical deionization deviceat various intervals. For example, current may be applied for 90% of thetime and turned off for 10% of the time while maintaining a constantfluid flow through the device. This may result in purified water havingabout 90% of impurities removed compared to water produced when thedevice is operated with current applied 100% of the time. Any cyclingmay be done over short time periods to avoid possible variations inproduct water quality that might result from extended periods of noapplied current. For example, cycling may occur less than every minuteor less than every 10 seconds.

An electrochemical deionization device may be heat sanitizable. If anelectrochemical deionization device is heat sanitizable, the surfaces ofthe device that are usually in contact with water during treatment maybe raised to a temperature and for a length of time adequate to kill orprevent the reproduction of pathogenic microorganisms. For example, thetemperature may be raised to greater than 50, 60, 70, 80, 85 or 90degrees Celsius. The device may be exposed to an elevated temperaturefor a period of time greater than 10 minutes, 30 minutes or 1 hour.Examples of electrochemical deionization devices that are heatsanitizable and methods of using them are provided in Arba, et al.,“Electrodeionization device and methods of use,” U.S. patent applicationSer. No. 09/954,986, Publication No. 20020144954, which is herebyincorporated by reference in its entirety herein.

In one embodiment, the electric current across a CEDI or RCEDI devicecan be adjusted to reduce or increase the amount of ionic material thatis removed from feed water. In many cases, no blending is required. Inanother embodiment, if a quality level for purified water is set, thenone or more process conditions can be adjusted in response to changes infeed water quality or to changes in the efficiency or performance of thesystem. This type of adjustment may also be employed when a similardesign is to be used at different installations having various feedwaters. For example, an electrochemical deionization device may beversatile enough to be used at locations providing feed waters frommunicipal sources or from well sources having either soft or hard watersupplies. A controller, such as a PLC, to adjust the operation of theelectrochemical deionization device may be included with the system andmay be sensitive to a number of factors, such as product water quality,water flow, feed water temperature, product water temperature, feedwater quality and operator input. Thus, a feedback control system may beimplemented to provide a consistent quality purified water responding tochanges in, for example, desired purified water quality, feed waterquality, temperature, use rates, and condition of the device and relatedequipment. Acceptable ranges for characteristics such as conductivity,hardness, alkalinity and TDS may be maintained with a single deviceindependent of changes to demand, feed water quality, temperature, anddevice efficiency, for example.

In some beverage applications, it may be preferred to reduce waterstorage. Systems based on RO devices typically require downstreamstorage to meet demand due, in part, to typically slow production ratesof the RO device. Any stored water may provide an environment formicroorganisms to grow, and rather than require additional disinfectionand monitoring, it may, in some cases, be more efficient to avoidstorage all together. Thus, an “on demand” type system such as providedin one embodiment of the present invention, may be ideal for use with afountain beverage production device or with any application thatbenefits from reduction of water storage, for example, beverage(including water) vending machines, coffee makers, dish washers, andrinse water for car washing facilities. An on demand system is one thatcan purify water for immediate use, for example, to be used less thanone minute after it is purified. An on demand system typically has nostorage tank between the water purification device and the point of use,e.g., the fountain beverage device. While there may be some piping ortubing between the water purification device and the point of use, thetotal volume of this piping or tubing is typically less than about oneliter. In some embodiments, there need not be a pump downstream of thewater purification device. An on demand system may also provide watersuitable for beverage production immediately after a term of non-use,for example, after an overnight period. The system may not need to berinsed prior to using the water.

As shown in FIG. 2, the system of the invention may include a number ofoptional components, such as a carbon filter 10. The carbon filter maybe first in a series of treatment devices. The pressure of the feedwater being supplied to carbon filter 10 may be monitored by pressuregauge 76. Carbon filter 10 may aid in the removal of any number ofcontaminants, including organic compounds as well as residualdisinfectants such as chlorine and chloramine. Any type of carbon filtermay be used, including cartridge types that may be preferable in abeverage production location because the cartridge can be quickly andeasily changed out when its removal efficiency drops. Alternatively, acartridge may be replaced simply based on time in service or on totalvolume throughput. Typically, beverage production sites are not equippedto regenerate carbon, making replaceable cartridges even moreattractive. Other types of carbon filters that may be used includecarbon block filters and granulated activated carbon (GAC). Multiplecarbon filters of different types may be used in parallel or in series.For example, a carbon block filter may be used in series with a filtercontaining GAC. Preferably, carbon filter 10 includes GAC that may beparticularly suitable for use in the beverage industry because of itsability to remove taste and odor compounds from a water supply. It ispreferred that carbon filter 10 is sized to minimize the pressure dropand flow restriction across the filter and to reduce the frequency withwhich it must be replaced while balancing these attributes against costand size considerations. More preferably, the filter may containadditives such as zeolites to aid in the removal of any heavy metals orother contaminants that may not be efficiently removed by carbon alone.

After the feed water passes through the carbon filter it may be fed toanother pretreatment device such as particulate filter 20. Particulatefilter 20 may be any filter capable of removing particulate matter fromthe feed water. Such filters include, for example, depth, screen,surface filters, and microporous filters. The filter media used may be adepth type filter such as a bed of greensand or diatomaceous earth or astring wound cartridge of cotton, polypropylene or other polymer.Alternatively, particulate filter 20 may be, for example, amicrofiltration or ultrafiltration membrane. The membrane may behydrophobic or hydrophilic and may be composed of, for example, PVDF,PTFE, polypropylene, polyethersulfone or polyethylene. The particulatefilter that is chosen may be selected based on the type of feed water atthe installed location. For example, if the feed water typicallycontains large amounts of suspended matter, a depth filter with a highloading capacity may be used. If the water is from a source that has notbeen treated to destroy microorganisms, a filter capable of removingmicroorganisms of concern, such as an ultrafiltration device, may bechosen.

Preferably, particulate filter 20 is a depth filter. More preferably,particulate filter 20 is a cartridge filter, and most preferably, it isa cartridge filter having filtration media composed of fibrous materialsuch as cotton or polypropylene with all parts that contact the waterbeing of food grade material. Cartridge filters provide for easyreplacement that can be performed by untrained personnel, thusminimizing the need for service calls at the installation. In addition,a variety of different cartridge types may be used with a singlecartridge housing unit, thus minimizing the need for offering differenthousing types with the water treatment system.

After the feed water has passed through particulate filter 20, it maythen be fed to an electrochemical deionization device, such as an RCEDIunit 30. An RCEDI is a continuous electrodeionization device that isconfigured to reverse polarity of the electrodes and alternateconcentrating and depleting compartments at about the time that thepolarity reversal takes place. The operation of such a device isdescribed in Giuffrida et al., U.S. Pat. No. 4,956,071. Such a devicemay contain a series of depleting and concentrating compartmentstypically bounded by either anion-permeable or cation-permeablemembranes. Each type of compartment may contain an ion exchange resin,typically a mixed-bed resin having both anion and cation exchangeresins. Ion exchange resins may also be homogeneous or doped and may bein layers. At least one cathode and at least one anode are provided thatsupply an electric current that splits water molecules into hydrogenions and hydroxide ions that constantly replenish the ion exchange resincontained in the depleting compartments. As water passes through thedepletion compartment, cations are exchanged for hydrogen ions with thecations being drawn through a cation permeable membrane into aconcentrating compartment under the influence of an applied electricfield. Likewise, anions are exchanged for hydroxyl ions and pass throughan anion permeable membrane into a concentrating compartment. De-ionizedwater then exits the depletion compartment and may be fed to anotherdepletion compartment for further purification or may be discharged foruse or alternative treatment. Water exiting the concentratingcompartment may pass through additional concentrating compartments to befurther concentrated or may be discharged to waste or an alternativeuse.

At a time either predetermined or determined later, for instance, by anoperator or a controller, the polarity of the RCEDI system 30 may bereversed so that the cathode(s) becomes the anode(s) and vice versa. Forexample, polarity may be switched at 10 minute intervals. At this time,or about this time, concentrating compartments become depletingcompartments and depleting compartments become concentratingcompartments. Soon, the water exiting the new depleting compartments maybe purer than that exiting the new concentrating compartments. Byalternating compartments in this manner, scale and deposit build-up maybe minimized as no one compartment serves as a concentrating compartmentfor an extended length of time. Thus, the resins, compartments,membranes, valving and piping may not be subjected to a level of solidsbuild-up that may occur in a system that does not use polarity reversal.In addition, the resin lifetime may be increased and the quality of theproduction water can be improved.

Cathodes and anodes used in an electrochemical deionization device maybe of the same material. These electrodes may have a base of, forexample, titanium, niobium or tantalum with a coating of platinum,ruthenium, iridium, or other dimensionally stable anode material. It ispreferred that a coating, when used, has a thickness from about 150 toabout 200 micro inches. This coating thickness, in some cases,corresponds to about 25 grams per square meter.

In some embodiments, a chiller may be placed in series with anelectrochemical deionization device. The chiller may be upstream of thedevice or downstream of the electrochemical deionization device and maybe upstream of a fountain beverage production device. When a chiller isplaced upstream of the electrochemical deionization device, a reductionin scale build-up may be realized.

In the embodiment shown schematically in FIG. 2, after feed water passesthrough particulate filter 20, it enters conduits 31 and 32 as well asconduit 33. Feed water flow and pressure may be measured at flow meter70 and pressure gauge 71. Conduits 31 and 32 can provide water to theconcentrating and depleting compartments (not shown) of the RCEDI stack.When conduit 31 is supplying feed water to the depleting compartments,conduit 32 is supplying feed water to the concentrating compartments.When the polarity is reversed, conduit 31 supplies the concentratingcompartments and conduit 32 supplies the depleting compartments.Purified water, the water that exits the depleting compartment (or theconcentrating compartment immediately after polarity reversal), is fedto either conduit 37 or conduit 38, depending upon which set ofcompartments is currently acting as the depleting one. The alternateconduit (either 37 or 38) that is carrying water from the concentratingcompartments is shuttled to waste line 60 or is recycled. The pathway ofeach of conduits 37 and 38 is controlled by either valve 80 or valve 81.The valves may be configured so that only one of either conduit 37 or 38is permitted to feed water to production conduit 39. Thus, if conduit 37is feeding production conduit 39, then conduit 38 will be directed towaste line 60. Pressure and flow of production water may be monitoredwith pressure gauge 72 and flow meter 73. Water quality may also bemeasured by a number of methods including optical, chemical andelectrical measurement devices. In some embodiments, a conductivitymeter 74 may be used, as it is a reliable way to monitor the ioniccontent of the water.

Conduit 33 may provide water, in series, to the anode and cathodecompartments (not shown) and when polarity is switched, valve 34 may beactivated so that water flow through these compartments is reversed.Water exiting the cathode and anode compartments passes through eitherdischarge conduit 35 or discharge conduit 36, both of which join to formconduit 40 that leads to either waste line 60 or is recycled. Flow inthe discharge conduits may be measured by flow meter 75.

Unlike conventional water softening techniques that use chemical ionexchange to remove calcium, magnesium and silica from feed water, thesystem of the present invention may provide for the removal of theseions without substituting sodium, potassium, or other cations in placeof the cations that are being removed. Calcium, magnesium and/or silicamay be replaced by, or exchanged for, hydrogen ions. Hardness can beremoved to levels that provide a water that is not so soft that taste isnoticeably affected.

Some water softening and water purification techniques may result in awater so pure that it may be corrosive, may be of reduced or elevatedpH, or may lack dissolved species that provide a taste component.Beverage vendors and licensors may be particularly concerned with thetaste of any water used to produce a beverage which may be sold under atrademark and, therefore, must be carefully quality controlled. This maybe particularly important at fountain outlets because of the largenumber of outlets, as well as the variation in water supplies that maybe used. For example, an RO system that might provide acceptable feedwater for fountain beverages at one outlet may actually provide water oftoo great a purity when installed at another outlet. Furthermore, due tothe nature of the operation of RO membranes, the purity of the outputcannot be varied. Embodiments of the invention that take advantage ofthe process control capabilities of electrochemical deionization devicesallow the output of the water to be controlled over a relatively narrowrange that contains neither too much nor too little TDS, hardness,alkalinity and other constituents. For example, hardness may becontrolled to a range of between 5 and 100 ppm (mg/L), between 10 and100 ppm, between 20 and 80 ppm, or between 30 and 70 ppm, measured ascalcium carbonate. Likewise, alkalinity may be controlled to be in arange of between 10 and 100 ppm, between 20 and 80 ppm, and between 30and 60 ppm, measured as calcium carbonate. In addition, theelectrochemical deionization device, such as an RCEDI, can be controlledto maintain pure water quality levels within a range of plus or minus 10ppm, plus or minus 20 ppm, or plus or minus 30 ppm. In addition, theseranges may be maintained for a range of feed waters including municipalwater and well water. In some embodiments, quality of water from afountain outlet may be controlled within a range allowing a fountain tosell not only flavored beverages, but to sell branded water as well.This may be done, in some cases, without adding minerals or otherspecies to a purified water. This may not be possible with other systemsbecause without flavoring and carbonation to help mask slight variationsin water flavor, a water available from a fountain outlet may not be ofconsistently adequate quality to be sold under a trademark.

Bicarbonate can be an important component of water that is used toprepare beverages. For example, too much bicarbonate in solution canconsume added carbon dioxide resulting in a flat carbonated beverage. Iftoo little bicarbonate is in solution, other characteristics such as pHmay be affected. For example, if bicarbonate levels are too low, thebuffering capacity of the water may be reduced and the addition of asmall about of acid may result in a very low pH. In one embodiment,purified water may be produced containing bicarbonate in a range thatdoes not consume added CO₂ but also is of adequate concentration toprovide adequate buffering capacity. Bicarbonate concentration in awater sample may be reflected in alkalinity measurements.

In one embodiment, purified water may be produced having a pH between 6and 9 and preferably between 6.5 and 8.5. These ranges can be obtainedby purifying the water with an electrochemical deionization device. Thewater may also contain some buffering capacity in the form ofalkalinity. The water may be produced without blending two or morewaters of differing pH and may be used for beverage production.

In one embodiment, water may be softened, that is, a concentration ofcalcium, magnesium and/or silica may be reduced and the process mayresult in a net reduction in ionic content. Unlike chemical ion exchangewater softening techniques, electrochemical deionization techniques mayremove cations such as calcium and magnesium without exchanging them forother cations such as sodium or potassium. In this manner, water can besoftened while simultaneously reducing the total ion concentration ofthe water.

In another embodiment, an electrochemical deionization device mayeliminate and/or reduce the quantity of viable microorganisms in a watersupply. For example, bypassing the water to a depletion compartment in aCEDI or RCEDI device, a large proportion of any microorganisms that maybe contained in the water can be rendered unviable by the operation ofthe device.

Conduit used in the system may be of any material capable of carryingwater. It is preferred that the conduit is tubing of food-grade polymer.The tubing may be of a small diameter and may be as short as ispractical, given peak flow and pressure requirements, to minimize thevolume of water that is “stored” in the tubing during periods ofnon-use. In embodiments where storage may be desirable, a storage tankmay be used. The storage tank may be in fluid communication with anelectrochemical deionization device and may be positioned upstream ordownstream of the electrochemical deionization device. The storage tankmay have a volume of greater than 1 liter, greater than 5 liters orgreater than 10 liters. A storage tank may be made of any materialappropriate for storing water such as, for example, glass, polymericmaterial, and stainless steel. In appropriate embodiments, a storagetank may be of food grade material.

A controller may be, for example, a microprocessor or computer, such asa process logic controller (PLC). A controller may include several knowncomponents and circuitry, including a processing unit (i.e., processor),a memory system, input and output devices and interfaces (e.g., aninterconnection mechanism), as well as other components, such astransport circuitry (e.g., one or more busses), a video and audio datainput/output (I/O) subsystem, special-purpose hardware, as well as othercomponents and circuitry, as described below in more detail. Further,the controller may be a multi-processor computer system or may includemultiple computers connected over a computer network.

The controller may include a processor, for example, a commerciallyavailable processor such as one of the series x86, Celeron and Pentiumprocessors, available from Intel, similar devices from AMD and Cyrix,the 680X0 series microprocessors available from Motorola, and thePowerPC microprocessor from IBM. Many other processors are available,and the computer system is not limited to a particular processor.

A processor typically executes a program called an operating system, ofwhich WindowsNT, Windows95 or 98, UNIX, Linux, DOS, VMS, MacOS and OS8are examples, which controls the execution of other computer programsand provides scheduling, debugging, input/output control, accounting,compilation, storage assignment, data management and memory management,communication control and related services. The processor and operatingsystem together define a computer platform for which applicationprograms in high-level programming languages are written. The controllerused herein is not limited to a particular computer platform.

The controller may include a memory system, which typically includes acomputer readable and writeable non-volatile recording medium, of whicha magnetic disk, optical disk, a flash memory and tape are examples.Such a recording medium may be removable, for example, a floppy disk,read/write CD or memory stick, or may be permanent, for example, a harddrive.

Such a recording medium stores signals, typically in binary form (i.e.,a form interpreted as a sequence of one and zeros). A disk (e.g.,magnetic or optical) has a number of tracks, on which such signals maybe stored, typically in binary form, i.e., a form interpreted as asequence of ones and zeros. Such signals may define a software program,e.g., an application program, to be executed by the microprocessor, orinformation to be processed by the application program.

The memory system of the controller also may include an integratedcircuit memory element, which typically is a volatile, random accessmemory such as a dynamic random access memory (DRAM) or static memory(SRAM). Typically, in operation, the processor causes programs and datato be read from the non-volatile recording medium into the integratedcircuit memory element, which typically allows for faster access to theprogram instructions and data by the processor than does thenon-volatile recording medium.

The processor generally manipulates the data within the integratedcircuit memory element in accordance with the program instructions andthen copies the manipulated data to the non-volatile recording mediumafter processing is completed. A variety of mechanisms are known formanaging data movement between the non-volatile recording medium and theintegrated circuit memory element, and the controller that implementsthe methods, steps, systems and system elements described herein and isnot limited thereto. The controller is not limited to a particularmemory system.

At least part of such a memory system described above may be used tostore one or more data structures (e.g., look-up tables) or equations.For example, at least part of the non-volatile recording medium maystore at least part of a database that includes one or more of such datastructures. Such a database may be any of a variety of types ofdatabases, for example, a file system including one or more flat-filedata structures where data is organized into data units separated bydelimiters, a relational database where data is organized into dataunits stored in tables, an object-oriented database where data isorganized into data units stored as objects, another type of database,or any combination thereof.

The controller may include a video and audio data I/O subsystem. Anaudio portion of the subsystem may include an analog-to-digital (A/D)converter, which receives analog audio information and converts it todigital information. The digital information may be compressed usingknown compression systems for storage on the hard disk to use at anothertime. A typical video portion of the I/O subsystem may include a videoimage compressor/decompressor of which many are known in the art. Suchcompressor/decompressors convert analog video information intocompressed digital information, and vice-versa. The compressed digitalinformation may be stored on hard disk for use at a later time.

The controller may include one or more output devices. Example outputdevices include a cathode ray tube (CRT) display, liquid crystaldisplays (LCD), touch screen display and other video output devices,printers, communication devices such as a modem or network interface,storage devices such as disk or tape, and audio output devices such as aspeaker.

The controller also may include one or more input devices. Example inputdevices include a keyboard, keypad, track ball, mouse, pen and tablet,touch screen, communication devices such as described above, and datainput devices such as audio and video capture devices and sensors. Thecontroller is not limited to the particular input or output devicesdescribed herein.

The controller may include specially programmed, special purposehardware, for example, an application-specific integrated circuit(ASIC). Such special-purpose hardware may be configured to implement oneor more of the methods, steps, simulations, algorithms, systems, andsystem elements described above.

The controller and components thereof may be programmable using any of avariety of one or more suitable computer programming languages. Suchlanguages may include procedural programming languages, for example, C,Pascal, Fortran and BASIC, object-oriented languages, for example, C++,Java and Eiffel and other languages, such as a scripting language oreven assembly language.

The methods, steps, simulations, algorithms, systems, and systemelements may be implemented using any of a variety of suitableprogramming languages, including procedural programming languages,object-oriented programming languages, other languages and combinationsthereof, which may be executed by such a computer system. Such methods,steps, simulations, algorithms, systems, and system elements can beimplemented as separate modules of a computer program, or can beimplemented individually as separate computer programs. Such modules andprograms can be executed on separate computers.

The methods, steps, simulations, algorithms, systems, and systemelements described above may be implemented in software, hardware orfirmware, or any combination of the three, as part of the controllerdescribed above or as an independent component.

Such methods, steps, simulations, algorithms, systems, and systemelements, either individually or in combination, may be implemented as acomputer program product tangibly embodied as computer-readable signalson a computer-readable medium, for example, a non-volatile recordingmedium, an integrated circuit memory element, or a combination thereof.For each such method, step, simulation, algorithm, system, or systemelement, such a computer program product may comprise computer-readablesignals tangibly embodied on the computer-readable medium that defineinstructions, for example, as part of one or more programs, that, as aresult of being executed by a computer, instruct the computer to performthe method, step, simulation, algorithm, system, or system element.

Operation of an electrochemical deionization system may be controlledeither manually or automatically. Preferably, operation is controlledautomatically by a controller such as a PLC. The PLC (not shown) may beprogrammed to control some or all of the functions of the system. Forinstance, the PLC may control the point at which the polarity of theRCEDI stack is to be reversed and may concurrently operate theappropriate valves to direct the flow of water as outlined above. Thismay be triggered by a pre-programmed condition based on, for instance,time or total output, or may be a more active system that is controlledby variables such as water quality, flow rates or pressure differentialsthat may be measured or detected through the use of various meters andgauges throughout the system that communicate with the PLC. For example,when a decrease in water quality is detected in conduit 39, this maysignal the PLC to reverse polarity and activate valves 80 and 81 toswitch the depleting and concentrating compartments. The PLC may alsoindicate certain conditions to the operator of the system, such as whena carbon or particulate filter cartridge needs to be changed, or, if aconsistent decrease in water pressure or quality is detected, the needfor servicing the stack. Off-site facilities or personnel may also benotified by, for example, telephone, internet, or radio. A PLC may alsobe used to adjust the power to the stack. This may be particularlyuseful in response to changes in feed water quality, demand in wateroutput, or if there is a decrease in the efficacy of the electrodes. Forexample, if the system is operating at a peak output of 3 gal/min anddemand is suddenly increased to 4 gal/min, an increase in power to thestack may be all that is required to meet the removal requirements ofthe increased volume.

In some embodiments, purified water may be post-treated. For example,after purification, water may be disinfected or preserved withchemicals, filtration, radiation or any combination of these.Post-treatment may include, for example, chemical disinfection, such aswith ozone, chlorine, chloramine or ammonia; heat disinfection, forexample, by heating the purified water to greater than 50, 70 or 85degrees C.; radiation disinfection, such as by irradiating with UVlight; and by filtration, such as by using microfilters, sand filtersand/or centrifugal sand filters that may be used to physically removemicro-organisms from the purified water. Post-treatment may be preferredwhen water is to be stored.

The present invention will be further illustrated by the followingexample, which is intended to be illustrative in nature and is not to beconstrued as limiting the scope of the invention.

EXAMPLE

To demonstrate the effectiveness of the present system, an RCEDI devicewas constructed and supplied with well water samples that containedcompounds and exhibited properties that are of concern for fountainbeverage production facilities. 14 different well water samples wereinitially analyzed for hardness, alkalinity, pH and TDS. The results ofthe initial pre-treatment analysis are summarized below in Table 1.

TABLE 1 Feed Water Parameters Average Median High Low Hardness (ppm 326326 336 318 as CaC0₃) Alkalinity (ppm 258 254 278 246 as CaC0₃) PH 7.77.8 8.0 7.3 TDS (ppm 442) 533 533 537 527

Each of the water samples was treated by feeding the water through anRCEDI device having the following features.

Device type:  20 cell-pair CEDI system Frequency of  10 minutes polarityreversal: Power Supply: 200 watts Flow Meters: Three flow meters formeasuring the dilute, concentrate, and electrode streams. PressureGauges: Five pressure gages to monitor feed, product, concentratestream, electrode stream and feed prior to carbon and particulatetreatment. PLC: Allen-Bradley MicroLogix 1000 PLC with four,double-pull, double-throw relays. Electrodes: Titanium plate electrodeswith platinum coating of about 30 micro inches.

The device was operated under conditions that would be practical for afountain beverage installation. These parameters are shown below inTable 2 below.

TABLE 2 System Parameters for the Reversal CEDI Module Number ofMeasure- Average Median High Low ments Product Flow (gpm) 0.96 0.95 1.200.89 71 Concentrate Flow 0.43 0.45 0.60 0.22 71 (gpm) Electrode Flow(gpm) 0.11 0.11 0.13 0.07 71 Current (amps) 2.4 2.4 2.6 2.1 62 Voltage(volts) 130.5 127 151 89 61 Pretreatment Feed 39.4 40 51 28 79 Pressure(psi) Stack Feed Pressure 30.3 30 40 27 68 (psi) Product Stream 21.8 2131 10 69 Pressure (psi) Concentrate Stream 26.9 26 38 15 69 Pressure(psi) Electrode Stream 12.5 10 34 5 69 Pressure (psi) Product PressureDrop 8.5 — — — — (psid) Concentrate Pressure 3.4 — — — — Drop (psid)

The properties of the water produced by the system were measured severaltimes for each sample being treated. These results, as well as typicalbeverage water requirements, are summarized below in Table 3.

TABLE 3 Product Water Parameters for the Reversal CEDI Module NumberTarget of Range Average Median High Low Samples Hardness ≦100 91 90 13262 80 (ppm as CaC0₃) Alkalinity  ≦85 71 70 109 52 80 (ppm as CaC0₃) pH6.5-8.5 6.7 6.7 7.1 6.5 74 TDS (ppm ≦500 166 165 227 122 80 442)

The waste stream from the concentrating compartments and electrodecompartments was also periodically analyzed during treatment. Theresults are shown below in Table 3.

TABLE 4 Concentrate/Electrode Water Parameters for the Reversal CEDIModule Number of Average Median High Low Samples Hardness (ppm) 732 736934 604 65 Alkalinity (ppm) 515 528 624 402 65 pH 7.7 7.7 8.0 7.3 63 TDS(ppm 442) 1097 1104 1359 940 65

A comparison of the results measured in the feed water and theproduction water compared to the beverage water specification shows thatthe system provides an effective method for bringing a typical feedwater into compliance with the beverage water requirements. The medianresults for hardness, alkalinity and TDS show that while the feed waterwas out of compliance for each of these parameters, the RCEDI processwas effective at improving the water quality to the required level. Itis also notable that the pH of the water was maintained at an acceptablelevel.

Further modifications and equivalents of the invention herein disclosedwill occur to persons skilled in the art using no more than routineexperimentation, and all such modifications and equivalents are believedto be within the spirit and scope of the invention as defined by thefollowing claims.

1. A method of purifying water comprising: providing feed water into anelectrochemical purification device; controlling hardness of the waterfrom the electrochemical purification device to a hardness level in arange of 5 ppm-100 ppm as CaCO₃; controlling alkalinity of the waterfrom the electrochemical purification device to an alkalinity level in arange of 10 ppm-100 ppm as CaCO₃; and supplying the water of controlledalkalinity and reduced hardness as purified water for human consumption.2. The method of claim 1 wherein the hardness level and the alkalinitylevel are obtained without blending with a purified water havinghardness of less than 5 ppm or with a purified water having analkalinity of less than 10 ppm.
 3. The method of claim 1 wherein at notime does any portion of the purified water have a hardness of less than5 ppm or an alkalinity of less than 10 ppm.
 4. The method of claim 1wherein the purified water has a pH of 6.5-8.5.
 5. The method of claim 1wherein the purified water has a TDS level in a range of from 10 ppm to200 ppm.
 6. The method of claim 1 wherein the hardness level is a rangeof 10 ppm-100 ppm as CaCO₃.
 7. The method of claim 1 wherein controllingthe alkalinity comprises adjusting an operating condition of theelectrochemical purification device to maintain the alkalinity of thepurified water in a range of from about 30 ppm to about 80 ppm, asCaCO₃.
 8. The method of claim 1 wherein the alkalinity level is in arange of from 30 ppm-50 ppm as CaCO3.
 9. The method of claim 1 whereinhardness is removed from the feed water without chemical ion exchange.10. The method of claim 1 further comprising pretreating the feed water.11. The method of claim 10 wherein pretreating the feed water comprisesat least one act selected from the group consisting of particlefiltering, chemical filtering, flocculating, aerating, disinfecting andchemically treating the feed water.
 12. The method of claim 1 whereinreducing hardness and controlling alkalinity are performed through thesame electrochemical purification device.
 13. The method of claim 12wherein the electrochemical purification device is an electrochemicaldeionization device.
 14. The method of claim 13 wherein theelectrochemical deionization device is an RCEDI.
 15. The method of claim1 wherein supplying the purified water comprises supplying at least aportion of the purified water to a fountain beverage device.
 16. Themethod of claim 1 wherein the hardness of the purified water ismaintained in a range of +/−20 ppm.
 17. The method of claim 1 whereinthe alkalinity of the purified water is maintained in a range of +/−20ppm.
 18. The method of claim 13 wherein controlling alkalinity of thewater comprises varying at least one process condition of theelectrochemical deionization device in response to at least one measuredproperty of the purified water.
 19. The method of claim 1 wherein thepurified water has a conductivity greater than about 20 μS/cm.
 20. Themethod of claim 1 wherein water is purified absent an RO device.
 21. Themethod of claim 1 further comprising post-treating at least a portion ofthe purified water by disinfecting.
 22. The method of claim 1 furthercomprising disinfecting at least a portion of the purified water withultraviolet light.
 23. The method of claim 1 further comprisingdisinfecting at least a portion of the purified water with amicrofiltration device.
 24. The method of claim 1 wherein the purifiedwater is supplied for immediate consumption.
 25. The method of claim 1further comprising post-treating at least a portion of the purifiedwater.
 26. A method for purifying water for beverage productioncomprising the steps of: supplying feed water to an electrodeionizationdevice to produce a purified water stream; regulating one or moreprocess conditions of the electrodeionization device in response to awater quality of at least one of a concentrate water stream from theelectrodeionization device, the feed water, and the purified waterstream; and feeding at least a portion of the purified water stream to abeverage production device.
 27. The method of claim 26 wherein the atleast a portion of purified water stream is immediately used to producea fountain beverage.
 28. The method of claim 26 wherein the feed wateris tap water.
 29. The method of claim 28 wherein a source of the tapwater is well water.
 30. The method of claim 28 wherein a source of thetap water is surface water.
 31. The method of claim 26 furthercomprising passing the feed water through a filter.
 32. The method ofclaim 31 wherein the filter is a cartridge filter.
 33. The method ofclaim 26 further comprising passing the feed water through a particulatefilter.
 34. The method of claim 33 wherein the particulate filter is astring wound filter.
 35. The method of claim 34 wherein the particulatefilter comprises polypropylene.
 36. The method of claim 34 wherein theparticulate filter comprises cotton.
 37. The method of claim 26 whereinthe feed water contains greater than about 500 ppm total dissolvedsolids and the purified stream contains less than about 200 ppm totaldissolved solids.
 38. The method of claim 26 wherein the feed watercontains greater than about 300 ppm hardness and the purified streamcontains less than about 100 ppm hardness and greater than about 10 ppmhardness.
 39. The method of claim 26 wherein the feed water containsgreater than about 200 ppm alkalinity and the purified stream containsless than about 100 ppm alkalinity and greater than about 10 ppmalkalinity.
 40. The method of claim 26 further comprising monitoring atleast one water quality of at least a portion of the purified waterstream.
 41. The method of claim 26 wherein the water quality a measuredconductivity of at least one of the concentrate water stream, the feedwater, and the purified water stream.
 42. The method of claim 26 whereinthe one or more process conditions comprises a parameter selected fromthe group consisting of a voltage, amperage, flow rate, and reversalcycle of the electrodeionization device.
 43. The method of claim 26,wherein the beverage production device is a fountain beverage productiondevice.
 44. The method of claim 26 wherein the electrodeionizationdevice is an RCEDI.
 45. The method of claim 26 further comprisingstoring at least a portion of the purified water stream for greater thanone minute before feeding the purified water stream to the beverageproduction device.
 46. The method of claim 26 wherein the purified waterstream is fed to the beverage production device in less than one minuteafter producing the purified water stream.
 47. The method of claim 26wherein the purified water stream comprises less than 100 mg/L andgreater than 10 mg/L total dissolved solids.
 48. The method of claim 26wherein regulating the one or more process conditions comprises reducinga purity of the purified water stream.
 49. A method of producing abeverage comprising acts of: introducing feed water into anelectrochemical water purification device; applying an electric currentthrough the electrochemical water purification device to produce apurified water stream having a desired hardness; adjusting at least oneoperating condition of the electrochemical water purification device toraise the alkalinity of the purified water stream to a desiredalkalinity; and adding a syrup concentrate to at portion of the purifiedwater stream to produce the beverage.
 50. The method of claim 49,wherein the desired hardness is a range of about 5 mg/L to about 100mg/L, as CaCO₃.
 51. The method of claim 49, further comprising an act ofadjusting the at least one operating condition of the electrochemicalwater purification device to reduce the alkalinity of the feed water tothe desired alkalinity.
 52. The method of claim 51, wherein the desiredalkalinity is in a range of about 10 mg/L to about 100 mg/L, as CaCO₃.53. The method of claim 52, further comprising an act of carbonating theat least a portion of the purified water stream.
 54. The method of claim53, wherein the electrochemical water purification device comprises areversible continuous electrodeionization device.
 55. The method ofclaim 53, further comprising an act of pre-treating the feed water priorto introducing the feed water into the electrochemical waterpurification device.
 56. The method of claim 55, wherein the act ofpre-treating the feed water comprises performing at least one offiltering the feed water, adding a flocculant to the feed water,aerating the feed water, and disinfecting the feed water.
 57. The methodof claim 53, further comprising an act of introducing at least a portionof the feed water into a chiller.
 58. The method of claim 53, furthercomprising an act of introducing at least a portion of the purifiedwater stream from the electrochemical purification device into achiller.
 59. The method of claim 49, wherein adjusting the at least oneoperating condition of the electrochemical water purification devicecomprises controlling the applied electric current to the producepurified water stream having a hardness in a range of between 5 mg/L and100 mg/L as CaCO₃.
 60. The method of claim 49, further comprising an actof controlling the applied electric current to produce the purifiedwater stream having an alkalinity in a range of between 10 mg/L and 100mg/L as CaCO₃.